PROJECT SUMMARY/ABSTRACT The pressing need to improve understanding of the mechanistic basis of transplant rejection and tolerance and to translate advances to the clinic, provides exciting opportunities for cutting-edge basic and translational scientists. There is a critical need for training programs that optimally prepare the next generation of transplantation researchers. With strong institutional support, the University of Pittsburgh School of Medicine (UPSOM) Starzl Transplantation Institute (STI) provides a unique academic environment, with an outstanding translational research base and culture, conducive to strong and comprehensive, broad-based training of young basic scientists and physicians in transplantation biology. Our established and proven Interdisciplinary Training Program in Transplantation Biology (TPTB) is very clearly delineated from other (successful) training programs at UPSOM. Our training program helps ensure that highly-trained investigators, strongly focused on transplantation, are available to assume leadership roles in academia, industry and government-affiliated research. Our highly-accomplished and well-funded participating faculty, further strengthened since our last renewal application by research leadership recruits, particularly in bone marrow and lung transplantation, have a very successful record of productive collaboration and strong commitment to training of young investigators. Expertise includes immunogenetics, ischemia-reperfusion injury, antigen-presenting cell, T and B cell biology, stem cell biology, tolerance induction, liver immunology, transplant infectious disease, chronic rejection, allo- and xenorecognition, xenotransplantation and human transplant immunology. A unique feature of our Training Program is that investigations range from those in invertebrates (a new trainer on the grant is expert in invertebrate allorecognition) and rodents to non-human primates and humans. Our trainees have been very successful publishing in leading journals, and in obtaining individual research fellowships, recognition and career development awards and faculty positions. Our goal is to produce outstanding, potentially independent investigators, highly conversant with fundamental and translational questions in transplantation biology and equipped with appropriate investigational, survival and career development skills. Pre-doctoral trainees are selected from graduate students enrolled in the Interdisciplinary Biomedical Graduate Training Program at UPSOM, including those in the medical scientist training program, who seek a PhD in transplantation biology. Based on successes achieved during the 2 previous funding periods of this Training Grant, the availability of well-qualified applicants and review of our original competing renewal application, we request support of 2 pre- doctoral trainees in year 11 and subsequent years. Postdoctoral trainees with MD, PhD, or dual degrees will be selected based on their outstanding potential and supported for 2 years. Support is requested for 2 postdoctoral trainees in year 11 and subsequent years. Our training faculty are strongly committed to ensuring appointments of members of underrepresented diversity groups to the grant.